1. Field of the Invention
The present invention relates to a code distinguishing apparatus for use in distinguishing unique words in communication among other purposes.
More particularly, the invention relates to a code distinguishing apparatus for use in switching over from one communication formula to another.
2. Description of the Related Art
For instance, Patent References 1 through 3 disclose methods to identify correlations among codes contained in received signals.
Or Non-Patent Reference 1, for example, discloses on pp. 298-299 a method by which a unique word is contained in the preamble of the transmittal frame of the TDMA system when it is transmitted.
Another example is a method of identifying the correlation between input data and a unique word, disclosed in Non-Patent Reference 2.
As the unique word in the transmittal frame is set to a value characteristic of each communication formula, it is possible to know by distinguishing the unique word what communication formula was used in transmitting the received data.
However, none of the references cited above takes note of this point and discloses a method by which the communication formula can be identified by distinguishing the unique word.
Patent Reference 1: Japanese Published Unexamined Patent Application No. Hei 11-196026
Patent Reference 2: Japanese Published Unexamined Patent Application No. 2002-148326
Patent Reference 3: Japanese Published Unexamined Patent Application No. Hei 5-7195
Non-Patent Reference 1: Masakazu Sampei, Application of Digital Wireless Transmission for Digital Wireless Communications, Pearson Education Japan, first print of first edition published on Sep. 1, 2002, ISBN4-89471-560-0
Non-Patent Reference 2: http://libl.nippon-foundation.or.jp/1998/0478/contents/076.htm